The present invention pertains to a reset device for a parking meter. More particularly, the present invention pertains to an infra-red radiation and receiving device, having minimum power requirements, for erasing any parking time remaining on a parking meter and resetting the parking meter when a vehicle parked in the space controlled by the parking meter has left, leaving the space empty. The parking meter reset device of the present invention is provided with a housing minimizing detection of stray radiation, such as from ambient sunlight, which could interfere with proper operation of the device. The housing is constructed to assure that, should someone attempt to thwart operation of the parking meter by blocking the transmission or reception of the radiation, only the reset device would be disabled, and the parking meter itself would continue to operate, functioning as a non-resettable parking meter.
Parking meters are frequently utilized to control parking spaces, particularly in urban areas. In the usual arrangement, each parking space has a parking meter assigned to it, and when a driver parks his car in that space, the driver is then to insert one or more coins into the parking meter and turn a control knob to actuate the parking meter. The parking meter then times a preset period of time, the length of which may be dependent upon the amount of money inserted by the driver, following which the parking meter indicates that the time for which payment was made has expired and generally displays a violation flag or other unpaid time indicator to indicate that there is no paid parking time remaining on the parking meter, and so if a vehicle is parked there, then the vehicle has not paid for the parking time or has been parked for a greater time than has been paid for. A police officer or a meter attendant then can cite the vehicle for a parking violation. Parking meters used in this fashion encourage a turnover of parking spaces, enabling more motorists to find a parking space, and provide revenue for the local government.
It often happens that a driver will park in a parking space and pay to park for a period of time, such as an hour, but will finish the business which has brought him to that location in a shorter time and so will leave the parking space with time remaining on the parking meter. A second motorist might then park in that parking space without paying, instead using some or all of the balance of the time from the first motorist. This is inequitable in that the second motorist is obtaining parking for which he is not paying. In addition, it deprives the local government of revenue that it might otherwise collect. To overcome this, parking meter reset devices have been developed which detect the absence of a vehicle in the parking space and reset the parking meter, returning display of the unpaid time indicator. By way of example, U.S. Pat. No. 3,018,615 shows a parking meter including a device which magnetically or electronically detects the presence or absence of a vehicle in the assigned parking space, and upon removal of the vehicle from the parking space and arrival of a subsequent vehicle, resets the parking meter. Likewise, U.S. Pat. No. 3,324,647 shows a parking meter including a proximity detector which resets the parking meter time indicator when the vehicle in the assigned parking space is removed.
U.S. Pat. No. 3,999,372 discloses a parking meter with a sonic transmitter and receiver for resetting the meter when the parked car is removed. The transmitter is shut off for a brief period following each pulse to enable reception of the reflected sonic pulse without confusion with the transmitted sonic energy. U.S. Pat. No. 3,535,870 shows a parking meter controller which transmits periodic bursts of ultrasonic energy and a receiver for receiving such energy after reflection from a vehicle in the controlled parking space. If the vehicle departs, the absence of reflections causes the parking meter to reset and deactivates the controller until the operator of the next parked vehicle reactivates the parking meter, thereby reducing power consumption. Other such resetting parking meters are shown in, for example, U.S. Pat. Nos. 2,535,472, 2,575,650, 2,652,551, 2,945,341, 3,018,615, 3,114,128, 3,141,292, 3,150,754, 3,166,732, 3,194,005, 3,154,175, 3,930,363, 4,043,117, 4,183,205, and No. 29,511.
Many of these prior art resetting devices utilize a sonic transmitter or a light transmitter located on the parking meter or its pole. The radiation from the transmitter is reflected by the vehicle in the parking space and is detected by a compatible detector also located on the parking meter or pole. When the detector does not receive a reflected signal for at least a preset time, it resets the parking meter. A problem experienced by prior art parking meter reset devices which detect reflected radiation, whether sonic or light, is the detection of erroneous radiation which prevents the device from resetting when it should. Thus, for example, ambient sonic or ultrasonic radiation can be detected by sonic devices which, therefore, do not reset even when no vehicle is in the controlled parking space. Likewise, sunlight, or possibly even a nearby street light, can be detected by devices utilizing light radiation, again resulting in the device not resetting even though the parked vehicle has left the controlled parking space. Another problem which can be experienced by prior art parking meter reset devices is failure to operate properly when the radiation path is blocked between the device and the parking space. Thus, for example, a bicycle may be parked and locked to the parking meter pole with a part of the bicycle or of the lock against the radiation transmitter and receiver, blocking the radiation path. Alternatively, a prankster might cover over the transmitter or the receiver, or both, in an attempt to prevent the device from receiving reflected radiation in the expectation that this would cause the parking meter always to show that the paid time had expired. A motorist doing this might then put a note on the parking meter saying the meter was not working properly and argue that this justified not paying for parking, or that payment had been made but the parking meter was inoperative.